The CDC Says 'Severely Obese' People Are at Greater Risk for COVID-19 Complications—but Are They Really?

Fat activists are terrified this distinction could mean life or death.

Editor's note: Obesity is considered a medical diagnosis and is therefore a word used in medical research. For the sake of clarity and to be accurate when reporting on studies, the term “obesity” is used when it’s referenced in the medical literature. In all other cases, when quoting fat activists, HAES-affliated dieticians and doctors, and in using the writer’s own voice, the terms "higher weight" and "larger body" are used.

The Centers for Disease Control and Prevention currently lists 10 different conditions and risk factors that can increase an individual's chance of developing severe illness from COVID-19—most of which are respiratory illnesses (like asthma and chronic lung disease) or conditions that can compromise a person's immune system (like diabetes and liver disease). But one reported risk factor on that list has created some controversy: severe obesity. Fat activists—individuals who promote the acceptance for and equality of larger bodies—worry that this decision, possibly backed by unclear data, is not only troublesome, but potentially harmful.

According to the CDC, severe obesity—defined by the agency as a body mass index (BMI) of 40 or above—puts people at higher risk for complications from COVID-19. The reasoning: Severe obesity reportedly increases the risk of a major COVID-19 complication known as acute respiratory distress syndrome (ARDS), and can cause difficulties with a doctor's ability to provide a person with respiratory support. The CDC adds that severe obesity is also linked to multiple serious chronic diseases and underlying health conditions, which can also increase the risk of severe illness from COVID-19.

A vocal number of fat activists, researchers, and health at every size- (HAES-) affiliated doctors, however, question whether the data shows this association at all, and say it's unclear how being higher weight could impact a person’s coronavirus risk. Instead, they believe, it’s likely that some members of the medical community are leaning on an already fatphobic culture to make dangerous assumptions about risk at higher weights—and those assumptions may put lives at risk.

What the research says about obesity and COVID-19.

What we know about COVID-19 is constantly changing, and the data on weight-connected complications from COVID-19 is no different. “For weeks, there were a lot of letters to the editor from scientific journals that were basically people expressing an opinion that ‘obesity’ was going to be a risk factor without any real evidence,” Christy Harrison, RDN, a certified intuitive-eating counselor and author of Anti-Diet: Reclaim Your Time, Money, Well-Being, and Happiness Through IntiutiveEating, tells Health.

Those letters have since turned into preliminary studies, some of which have been published in scientific journals; others that are only available on preprint servers. One of the largest studies identifying a link between obesity and severe illness from COVID-19 to date, shared on the preprint server MedRxiv and not yet peer-reviewed, comes from researchers at NYU Langone Health who analyzed data from more than 4,000 COVID-19 patients who sought care at the hospital between March 1 and April 2.

According to researchers, hospital admission for COVID-19 was primarily dependent on age (those ages 65 and up were most likely to be admitted), followed by obesity (defined by study authors as a BMI of over 30), and a history of heart failure. Leora Horwitz, MD, the study's senior author and associate professor in the Department of Population Health at NYU Langone added in a press release that "obesity is more important for hospitalization than whether you have high blood pressure or diabetes, though these often go together, and it’s more important than coronary disease or cancer or kidney disease, or even pulmonary disease."

The study’s authors were looking to see if obesity itself, uncoupled with diseases, could put someone at risk for complications, says Horwitz’s co-author, Christopher Petrilli, MD, Assistant Professor of Medicine at NYU Langone Health. “We do find that obesity is indeed an independent risk for development of severe COVID-19 disease requiring hospitalization or intensive care, even accounting for the fact that many of those patients also have diabetes or heart disease,” he tells Health.

The NYU study is the first large paper that uses advanced statistical models to identify independent risk factors for COVID-19 complications, Dr. Petrilli says. But Harrison, who recently wrote an opinion piece for Wired arguing that COVID-19 does not discriminate based on BMI alone, points to two other papers that also provide some plausible findings on the link between COVID-19 and obesity, specifically labelling a high BMI as a risk.

The first is a CDC Morbidity and Mortality Weekly Report, initially published on April 8, which looked at the clinical data of 1,482 patients hospitalized due to COVID-19 during March 2020, the first month of US surveillance. Among those hospitalized, 178 patients—or 12% of the entire study sample—had available information on underlying conditions, and of those 178 patients, 48.3% were classified as obese. The other, a small French study published in the journal Obesity, looked at at 124 COVID-19 patients admitted to intensive care. Researchers concluded that, next to being male, the risk for the need of invasive mechanical ventilation (aka, use of a ventilator) increased as BMI increased, and was greatest in those with a BMI of 35 or greater.

HAES-affiliated doctors and dietitians say this data shouldn’t be taken at face-value.

Although Harrison does point to those few studies that seem plausible, she notes that research looking at people of higher-weight is typically biased and often flawed. In fact, much of the data we currently have seems to be nothing more than a mirror of what body size looks like in the general population. “Is [high-weight] actually a risk factor, or is it an association, or does it reflect the general population? Quite a few of the reports I’ve looked at pretty closely mimic the general population,” says Michelle May, MD, a retired family physician who now teaches about mindful eating.

One such report from the Intensive Care National Audit and Research Centre in the UK takes the step to superimpose a graph of the country’s BMI distribution over the BMI data collected from patients hospitalized with coronavirus. While the graph does show a greater number of obese (clinically defined by researchers as having a BMI of 30 or greater) patients than those not considered obese, it also shows a greater number of higher-weight people in the UK overall. The number of severely obese patients (those with a BMI of 40 or greater) also looks on track with the percentage in the general population.

Reports from the U.S. show similar trends. Data from a long-term care facility in King County, Washington published in the New England Journal of Medicine, examined confirmed COVID-19 cases in residents, personnel, and visitors, and found among those with data on underlying conditions, 22% had a BMI of 30 or greater—the same percentage of King County residents in general who are considered obese, according to the latest data from the county's department of public health. The same stands for the CDC's report showing that 48.3% of those with available data hospitalized for COVID-19 were also considered obese—very similar to the most recent data from the CDC, which reported in 2018 that the prevalence of obesity in the US is 42.4%.

On average, the numbers of high-weight critically ill COVID-19 patients in the U.S. seems to be roughly the same as the numbers of high-weight people generally, implying what we already know: This virus is hurting all of us.

Remember: Social factors matter in COVID-19 diagnoses and instances of higher weight, too.

One big flaw of the plausible studies Harrison pointed to is that they don’t control for important social circumstances like race, socioeconomic status, and even quality of care, she wrote in Wired. Low socioeconomic communities, for example, tend to have a greater percentage of higher-weight individuals, and people of low socioeconomic status also make up a large percentage of the essential workers who have to go outside and risk catching COVID-19 every day. Unsurprisingly, those same social factors also account for why African-American US citizens are dying from COVID-19 at alarming rates, compared to their white counterparts. (In Chicago, for example, African Americans only account for 30% of the population—but make up 68% of the coronavirus death toll.) According to Dr. May, the relationship between COVID-19 and higher-weight people is "a multifactorial issue where social determinants of health like income, violence, trauma, discrimination, and racism compound."

“Fatphobia is behind most interpretations of data regarding the coronavirus and high weight,” says Lindo Bacon, PhD, author of Health At Every Size. “Because you can’t disentangle the effect of fatness versus being a victim of fat stigma, it's dubious to attribute anything that shows up in large bodies to fatness itself.” Being at a higher weight—especially when that weight falls under the CDC’s category of severe obesity—in a fatphobic culture means facing sometimes daily discrimination: people calling you names as you walk down the street, giving you dirty looks as you try to buy groceries, or mooing at you from passing cars. “Facing the emotional trauma of weight stigma for years could put people at risk,” says Louise Metz, MD, an internal medicine physician in North Carolina. Previous research shows that facing constant discrimination like this can increase the likelihood of chronic inflammation, which is in turn linked to diseases that increase COVID-19 risk such as heart disease, cancer, asthma, and diabetes.

“There are other causal factors that could mediate what we’re seeing, too,” Dr. Metz says. She gives the example of weight cycling or “yo-yo dieting.” Many higher-weight people have a history of weight cycling, diets are ineffective and lead to regaining weight in the majority of people. Much like weight stigma, research has shown that weight cycling increases risk of illnesses like diabetes and hypertension, Dr. Metz says.

Due to weight bias in health care, higher-weight people are also more likely to put off seeking medical care, adds Dr. Metz. This could mean two things: Higher-weight people checking into the hospital with COVID-19 symptoms could have started out sicker than others, having spent years avoiding medical care; or, they may continue to avoid going to the doctor to check on possible COVID-19 symptoms until their symptoms are already dangerous.

In that vein, a group of doctors who wrote an editorial in the journal Obesity pointed to infrastructure issues that could arise once higher-weight patients get to the hospital. “Persons with severe obesity who become ill and require intensive care present challenges in patient management—more bariatric hospital beds, more challenging intubations, more difficult to obtain an imaging diagnosis (there are weight limits on imaging machines), more difficult to position and transport by nursing staff.” Higher-weight people could face poorer care at the hospital simply by the fact that the hospital doesn’t have enough equipment or because doctors there weren’t trained to intubate someone like them.

With all of these factors in the background, it’s impossible to prove that high weight is an independent risk factor for complications from COVID-19, especially with the preliminary data we have now. "My view on this is that they were looking for it to be fat bodies," Harrison says of the data and the CDC’s inclusion of severe obesity in their high-risk groups. “And when you go looking for something like that, framing your research in that way, sometimes you find it."

Interestingly enough, there's a chance being higher-weight may protect against serious COVID-19 complications.

Among the leading causes of COVID-19-related deaths is a condition called acute respiratory distress syndrome (ARDS), an inflammatory lung injury that leads to dangerously low levels of oxygen in a person’s blood. ARDS is one reason hospitals desperately need ventilators to treat people with severe COVID-19 symptoms.

It's a dangerous and often fatal condition, and even the CDC noted an increased risk of developing ARDS as a reason why severe obesity is part of their high-risk criteria. And yet, a 2017 meta-analysis in the journal Critical Care looked at studies involving both ARDS and BMI between 1946 and 2016, and found that being at a higher weight, even that which qualifies as severe obesity could provide a protective benefit from dying from the condition. Compared to underweight and normal weight—which is actual verbiage from the study, qualifying normal weight as a BMI of 18.5-25, and underweight as a BMI below 18.5—patients in these studies, patients who were considered overweight (a BMI of 25-30), obese (a BMI of 30-40), and severely obese (a BMI of over 40) survived more often.

These findings in particular—that higher-weight may have protective benefits against specific diseases like ARDS and was ultimately named the "obesity paradox" due to multiple studies on the topic—have puzzled medical researchers for years. One possible explanation, according to another 2017 research article published in the journal Critical Care, suggests evidence of a "pre-conditioning cloud" in which obesity may cause low-grade inflammation that "subsequently protects the lung against further insults."

Findings like these are important, especially in the context of COVID-19, says Harrison. "Even if larger body size does end up being a risk for hospitalization or ICU admission, which there's so much bias in that I can't tell for sure, but even if there was an extra risk there may be still a benefit in terms of lower likelihood of death from COVID-19 to being in a larger body,” she says. Ultimately, like the data we have connecting COVID-19 and high weight, these studies also show correlation and not causation, so it’s impossible to say that being higher weight actually protects people from ARDS, but Harrison says we may end up seeing that tradeoff.

Regardless, fat activists worry that being designated a high-risk group could impact their care—and eventually, their lives.

No matter the potential protective benefits of having a larger body, or the possible link between higher-weight individuals and hospitalization rates, fat activists worry that simply being designated as a high-risk group could lead to greater discrimination at hospitals and keep them from getting access to needed resources should they get sick. And even if a higher weight were undoubtedly an independent risk for complications from COVID-19, there's currently no advice specifically for those in larger bodies on how to protect themselves. (The CDC's handout for people in at-risk groups gives the same advice everyone else gets: stay home, wash your hands, avoid close contact, clean and disinfect surfaces, and stay away from cruises.)

Instead of truly helping higher-weight people, fat activists also worry that being labeled a high-risk group only incites more blame on those in larger bodies, implying that if they did get sick and had to go to the hospital, they did it to themselves. In turn, those implications only increase fear, possibly leading to more discrimination from healthcare providers for the high-weight people who need medical care.

Hospitals have already started talking about this possible triage situation and some reports suggest that some hospitals may take a utilitarian approach that favors the people doctors think have the best chance of survival. In that case, being labeled a high-risk group could easily cause higher-weight people to be pushed aside because doctors assumed they’d get sicker than the person down the hall. Although it’s not yet reality, Harrison says it's "morally create a hierarchy of who gets care based on these pre-existing stigmas that exist in our society: stigmatizing people with larger bodies, stigmatizing people with disabilities, stigmatizing older people."

In an effort to push back, higher-weight people are using hashtags like #weareessential, #nobodyisdispoable, and #noICUgenics on Instagram and Twitter to beg healthcare workers to consider their lives, should we reach a point when resources like ventilators are in short supply and doctors have to choose who gets treatment and who does not. In an open letter to medical professionals, those in the #nobodyisdisposable movement wrote: “Before COVID-19, marginalized communities have had reason to fear bias in medical settings. We are terrified of being killed by the people who are supposed to care for us. Let’s protect each other and fight for the resources and policies we need to get through this emergency together.”

The information in this story is accurate as of press time. However, as the situation surrounding COVID-19 continues to evolve, it's possible that some data have changed since publication. While Health is trying to keep our stories as up-to-date as possible, we also encourage readers to stay informed on news and recommendations for their own communities by using the CDC, WHO, and their local public health department as resources.

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